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February 8, 2009

Genetic Selection Opens New Doors For Fertility Clinics

by Sam Savage

With the advances in genetic screening and fertility, the future of prospective parents being able to pick and choose what traits they want in their yet-to-be conceived children may not be too far away. But for biologists, such ideas beg many questions about ethics and evolution.

Charles Darwin first set down the principle of species change through natural selection.

But when it comes to humans, "natural selection" is becoming increasingly harder to define. It has already been challenged by medicine, habitat, diet and other factors that affect lifespan, reproduction and survivability.

The ability of genetic selection would mean our species' evolutionary path would be even more radically changed. And it's vision that doesn't seem too far away.

According to an AFP report, clinics all over the U.S. already provide would-be parents in-depth profiles of potential sperm and egg donors.

The Xytex Corporation in Atlanta already offers a long list of genetically coded physical attributes, including length of eyelashes, the presence of freckles and whether ear lobes are detached.

Most heterosexual couples shop in this market to compensate for either male or female infertility, yet there are no such laws that prevent matching a donor egg with donor sperm to create an embryo that can be purchased and implanted in the buyer's womb.

One "embryo bank" in Texas offered this option before it reluctantly withdrew the procedure under an ethical firestorm.

Experts believe even parents who don't need outside help to procreate may soon be signing up for "preimplantation genetic diagnosis" of embryos to check not only for genetic defects and disease but also for sex and desirable traits as well.

Marcy Darnovsky of the Center for Genetics and Society in Oakland, California, told the AFP that science needs to look carefully at these selection technologies.

She said while it isn't bad to have a desire for a girl or a boy, you can now find prospective mothers using chatrooms and bulletin boards who don't just want a girl, but a particular kind of girl.

Darnovsky wondered, "Ëwhat are they going to do if they don't get that kind of child, take them back?'

The leap from genetic selection to genetic engineering may be an even more problematic scenario for some.

Experts say it could happen in two ways: For example, gene therapy alters genes in a diseased organ in order to affect a cure.

But changes wrought by so-called germ-line therapy alter the blueprint itself, the human genome, and would thus be passed on to offspring.

Peter Ward, a scientist at the University of Washington and author of "Future Evolution", said the pressure to change genes will probably come from parents wanting to guarantee their child is a boy or a girl, or to endow them with beauty, intelligence, musical talent or a sweet nature.

Ward said last month in the journal Science that germ-line therapy may be out of reach, for now, but were science to master the genome, the temptation to tweak it to increase smarts, looks and longevity would be overwhelming.

"One day, we will have it in our power to bring a new human species into this world," he said.

However, Steven Pinker, an evolutionary biologist at Harvard University, believes all of these worries are misplaced.

"Genetics is far too complex to allow for easy manipulation of human traits," he said.

He pointed out that nearly all diseases and traits are determined not by one or two genes but the interaction of many. In other words, there is no such thing as a master gene for intelligence or musicality.

Pinker doubts that parents would take a risk greater than five percent that something would go wrong.